From 82e4eda664d40ef60829e27d84b1610c2f4070cd Mon Sep 17 00:00:00 2001 From: David Herrmann Date: Tue, 7 Jun 2016 10:38:33 +0200 Subject: sd-netlink: fix deep recursion in message destruction (#3455) On larger systems we might very well see messages with thousands of parts. When we free them, we must avoid recursing into each part, otherwise we very likely get stack overflows. Fix sd_netlink_message_unref() to use an iterative approach rather than recursion (also avoid tail-recursion in case it is not optimized by the compiler). --- src/libsystemd/sd-netlink/netlink-message.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) (limited to 'src/libsystemd/sd-netlink') diff --git a/src/libsystemd/sd-netlink/netlink-message.c b/src/libsystemd/sd-netlink/netlink-message.c index 86d8dee867..df3b3c922e 100644 --- a/src/libsystemd/sd-netlink/netlink-message.c +++ b/src/libsystemd/sd-netlink/netlink-message.c @@ -120,7 +120,9 @@ sd_netlink_message *sd_netlink_message_ref(sd_netlink_message *m) { } sd_netlink_message *sd_netlink_message_unref(sd_netlink_message *m) { - if (m && REFCNT_DEC(m->n_ref) == 0) { + sd_netlink_message *t; + + while (m && REFCNT_DEC(m->n_ref) == 0) { unsigned i; free(m->hdr); @@ -128,9 +130,9 @@ sd_netlink_message *sd_netlink_message_unref(sd_netlink_message *m) { for (i = 0; i <= m->n_containers; i++) free(m->containers[i].attributes); - sd_netlink_message_unref(m->next); - - free(m); + t = m; + m = m->next; + free(t); } return NULL; -- cgit v1.2.3-54-g00ecf